8.1.4 Manual update from PrestaShop 1.7.6.7 to PrestaShop 8.1.4 using CLI method fails - Symfony ClassNotFoundError

[reinix]

Hi,

i'm trying to update manually from PrestaShop 1.7.6.7 to PrestaShop 8.1.4 using the CLI method outlined here: 

https://github.com/PrestaShop/docs/blob/131c273ba2b5b162206673298fb0c3c182fd1147/basics/keeping-up-to-date/upgrade-module/upgrade-cli.md

The upgrade module v5.0.1 has been installed via shop backend (module manager).

How can i avoid this error which comes from "Symfony" obviously?

All previous steps were running fine.

(Linux Debian 12.5 / Plesk Obsidian 18.0.59 / PHP 7.4.33, also used for CLI)

Thanks!